1. Field of the Invention
The present invention relates to an optical waveguide component used with optical fiber connectors connected to the end faces thereof, and more particularly, to an optical waveguide component used with optical fiber connectors connected thereto without alignment.
2. Description of the Prior Art
An optical waveguide component, which has an optical waveguide core portion of a predetermined pattern embedded in a cladding portion, is used with single- or multi-core optical fiber connectors connected to both end faces thereof.
There are two methods for connecting the optical fiber connectors. In one method, the end face of each optical fiber connector is butted to an end face of the optical waveguide component, the respective optical axes of optical waveguide cores are aligned individually with those of optical fibers, and thereafter, the connector and the component are fixed by bonding or welding. The other method is a non-alignment connecting method, which will be described below.
The non-alignment connection is applied to an optical waveguide component, such as the one shown in FIG. 1, for example.
In an optical waveguide component A, as shown in FIG. 1, an optical waveguide core portion 2 is formed on an optical waveguide substrate 1, such as a silicon substrate with a predetermined thickness. The core portion 2, which comprises of optical waveguide cores 2a of quartz glass arranged at predetermined pitches in the crosswise direction of the substrate 1, is embedded in a cladding portion 3 of quartz glass (with a lower refractive index than that of the core material).
Two grooves 3a and 3a, which have a predetermined width and depth and extend in the lengthwise direction of the substrate 1, are marked in the cladding portion 3 and the substrate 1, ranging from the top of the cladding portion to the near portion of the bottom of the substrate, by means of a dicer, for example. In doing this, the optical waveguide core portion 2 is used as a positioning reference.
Guide pins 4a and 4b with a predetermined diameter are arranged in the grooves 3a and 3a, respectively, and the whole resulting structure is pressed by means of a hold-down plate 5 so that the pins 4a and 4b are fixed in the grooves 3a and 3a.
On the other hand, optical fiber connectors 6 each contain optical fibers which are arranged at the same pitches as the cores 2a of the core portion 2 of the optical waveguide component A. Further, pin holes 6a and 6b are formed on either side of the connectors 6 so as to be coaxial with the guide pins 4a and 4b, respectively.
In connecting each optical fiber connector 6 to the optical waveguide component A, the guide pins 4a and 4b are inserted into the pin holes 6a and 6b, respectively, of the connector 6, and the respective end faces of the component A and the connector 6 are brought into contact with each other. Then, the component A and the connector 6 are pressed against each other by means of, for example, a spring clip 7.
Thereupon, the respective optical axes of the cores 2a of the optical waveguide core portion 2 are individually in alignment with the optical fibers of the optical fiber connector 6. Thus, the optical connection is completed without requiring an alignment operation.
According to the non-alignment connecting method described above, however, cracks may possibly be caused at the junction between the optical waveguide component A and the optical fiber connector 6, in the vicinity of the grooves 3a and 3a of the component A, as the guide pins are inserted or removed, or if the smallest load is applied on the junction after the component A and the connector 6 are connected.
The grooves 3a and 3a of the optical waveguide component A are cut in the top face of the cladding portion 3 to a depth such that they can receive the guide pins 4a and 4b, respectively. If the substrate 1 is about 1 mm thick, for example, the depth of the grooves 3a and 3a in the substrate is great relative to the thickness of the substrate, so that the strength of the substrate may be lowered in some cases.
In an optical waveguide component designed so that the pattern of the cores 2a of the optical waveguide core portion 2 is freely formed in a two-dimensional expanse, the two-dimensional core pattern sometimes may be cut into pieces as the grooves 3a and 3b are formed. Avoiding this situation entails an increase in cost for groove cutting or in the overall size of the optical waveguide component A.